It is well known that vehicles are equipped with airbag systems and other inflatable systems to provide protection to a driver and passengers against injury during high-impact vehicle collisions. An airbag system for a steering wheel generally works by rapidly inflating a flexible bladder disposed within the steering wheel hub when the vehicle experiences a severe, high-impact collision. When the airbag system is deployed, the fully inflated bladder cushions and distributes load across the driver's head and chest and protects these body parts from hitting the vehicle interior, including the steering wheel, dashboard and car window. Conventional airbag systems comprise several sensors positioned at various locations in the car to detect a high-impact collision. If the sensors register the level of impact above a threshold, they immediately ignite a propellant to inflate the bladder. In the U.S., regulations require that airbags deploy in high-impact crashes at least equivalent in deceleration to a 23 km/h, or 14 mph, barrier collision (www.nhtsa.gov). A vehicle colliding with a stationary barrier at 14 mph generates approximately 7 G's of force. Collisions at a minimum speed of 30 mph as well as head-on collisions at 25 mph generate similar amount of force. Examples of conventional airbag systems for protection during high-impact collisions are disclosed in various patents, including U.S. Pat. Nos. 6,220,630, 6,648,367, 6,893,044 and 7,481,455.
Although conventional steering wheel airbag systems provide protection to a driver, such protection is limited to the driver's head and chest. The driver's fingers, hands, wrists, arms, elbows, and shoulders (herein “upper extremities”) are usually left defenseless, and thus, are prone to injury during the vehicle collision. The vibrations and pressure of the impact are transferred through the steering wheel to the driver's upper extremities. This instantaneous transmission of large vibrations and high pressure can cause traumatic carpal tunnel syndrome (CTS), other upper-extremity neurological injuries, stress/sprain/strain-related injuries in the upper extremities, as well as fractures and dislocations in areas of the wrists, such as distal radius Colles' fracture, hand fractures and dislocations, such as metacarpal fractures (e.g., Bennett's fracture of the thumb), elbow fractures, and shoulder fractures. Any of the above medical conditions, injuries, and fractures/dislocations can also be aggravated if the driver's arms are outstretched and gripping the steering wheel in an extended wrist position when the vehicle collision occurs. Both low-impact and high-impact collisions can cause CTS, neurological injuries, and stress/sprain/strain-related injuries in the driver's upper extremities. Indeed, CTS and other upper extremity injuries are a major concern in low-impact collisions, whereas in high-impact collisions, full body traumatic injuries require the most attention.
In view of the above, conventional steering wheel airbag systems fail to provide any protection for the driver's upper extremities in a vehicle collision, especially in a low-impact collision (e.g., a collision comparable to hitting a solid barrier at less than 14 mph, general collisions at speeds less than 30 mph, head-on collisions at speeds less than 25 mph).
Some vehicle safety systems may provide for some form of protection to the driver's upper extremities. For example, U.S. Pat. No. 6,382,661 to Sutherland discloses a steering wheel apparatus adapted to protect a driver in a vehicle collision when the driver is not seated properly in the driver seat. The apparatus includes a steering wheel rim, or handgrip, having at least one inflatable bladder mounted thereon and an internal inflator which inflates the bladder by passing fluid through channels and fluid openings created in the rim. However, the apparatus does not cover the entire steering wheel rim. Only certain portions of the steering wheel are adapted with the bladder. As such, the apparatus is only effective if the driver is gripping a section of the steering wheel rim that has the bladder. Furthermore, the bladder is not specifically designed to provide protection to the driver's hands and arms or configured to inflate during a low-impact collision. In the event of a high-impact collision, the bladder helps to re-position an out-of-position driver (e.g., driver leaning forward in the car seat) as the standard steering wheel airbag begins to deploy. The safety system merely improves the effectiveness of the airbag system in protecting the driver's chest and head against injury. The apparatus also does not include a controller for adjusting the manner in which the bladder inflates based on the nature and characteristics of the collision.
U.S. Pat. No. 5,207,713 to Park discloses a safety cover attached onto a steering wheel handgrip which absorbs an impact between the driver's body and the steering wheel during a collision accident. The safety cover comprises an impact reducing section adapted to wrap around the entire circumferential surface of the steering wheel handgrip as well as a fixing section for mounting the impact reducing section to the handgrip. When the impact reducing section is filled with fluid, the cover exerts pressure against the steering wheel to assist in mounting the cover. Nevertheless, the cover may still rotatably move about the steering wheel handgrip while the driver is grasping the cover. This adversely affects the driver's ability to properly maneuver and maintain firm control over the steering wheel. During a collision, the impact force can also shift the cover about the steering wheel and thereby reduce its effectiveness. More importantly, the cover does not provide for “deployment” (i.e., rapid inflation of additional fluid) at the moment of collision. The cover also lacks a controller interfaced with an inflation device to adjust the amount of fluid contained within the impact reducing section. Therefore, the cover, which is preconfigured with a specific amount of fluid, may not sufficiently protect the driver's upper extremities against an impact with the steering wheel or absorb the vibrations transmitted to the driver's upper extremities during a collision.
While some steering wheel safety systems may provide improvements over conventional airbag systems, they still suffer from several disadvantages. One disadvantage is that current safety systems fail to provide sufficient protection to the upper extremities during a vehicle collision. Current safety systems also may not function during low-impact collisions, which can still cause CTS, neurological injuries, stress/sprain/strain injuries, and fractures/dislocations in the upper extremities. Another disadvantage is that the arrangement of the safety system may prevent the driver from being able to safely operate the steering wheel—and thus the vehicle—due to rotational movement of the safety system relative to the steering wheel. Further, safety systems do not incorporate a controller integrated with an inflation device to adjust the nature of deployment based on characteristics of the collision. Moreover, current safety systems fail to provide an adjustable grip for damping the typical vibrations transmitted through the steering wheel during normal driving operations. Standard airbag systems and steering wheel safety systems, therefore, fail to protect a driver's upper extremities during all stages of driving, including normal driving operations, low-impact collisions and high-impact collisions.